Exam 2 Flashcards
(255 cards)
what is ventilation
the movement of air btw atmosphere and the alveoli-by inhalation/exhalation, higher to lower pressure
minute ventilation
volume inhaled/exhaled per minute = 7500ml at rest
alveolar ventilation
volume of fresh gas entering respiratory zone available for gas exchange per minute
if rapid breathing, how are PaCO2 and alveolar ventilation impacted
alveolar vent is increased and CO2 decreases
diffusion
exchange of O2 and CO2 b/w pulmonary capillaries and the alveoli
what impacts diffusion (4)
- Affected by surface area available for diffusion
- Affected by thickness of alveolar-cap membrane
- partial pressure of gas across the membrane
- and solubility and molecuar characteristics of the gas
perfusion
flow of blood through the pulmonary capillary bed
what is transport
Oxygen and co2 being circulated in the blood and to and from the cells
how is o2 transported
RBCs - hemoglobin (97%)
Dissolved in blood (3%)
how is co2 transported
Dissolved in blood (10%)
Attached to hemoglobin (30%)
Bicarbonate in bloodstream (60%)
What drugs can go down ET tube because they are metabolized in lung tissue?
Lidocaine
Epi
NARCAN
Atropine
conducting airways
No actual gas exchange takes place here (anatomic dead space)
Nasopharynx warms, humidifies and filters air
Includes naso and oropharynx, trachea, bronchi, bronchioles, and terminal bronchioles
respiratory airways
Respiratory bronchioles, alveolar ducts, and alveolar sacs
Surrounded by smooth muscle
type 1 alveolar cells
responsible for gas exchange
type 2 alveolar cells
secrete surfactant
Macrophages present to remove foreign substances
what is the v/q relationship
Ventilation/perfusion (V/Q) relationship
Measure of how well someone is ventilating vs perfusing
what is the normal v/q
Normal is 0.8 - 1 (4L/minute of ventilation to 5L / minute of perfusion)
what 5 things influence V/Q
- anatomical dead space
- alveolar dead space
- anatomical shunt
- physiological shunt
- silent unit
anatomical dead space
Conducting airways
*Tubing from ET tube back to ventilator - adds dead space
High V/Q ratio (alveolar dead space)
-Normal or good ventilation with decreased or no perfusion
-When regions in respiratory airways are ventilated but not perfused
-ex: pulmonary embolism, cardiogenic shock (amount of o2 in alveoli is so low)
shunt
blood bypasses alveoli w/o picking up O2
anatomical shunt
Patent ductus arteriosus
ASD
VSD
Patent foramen ovale
Mixing of oxygenated and deoxygenated blood → dilutes oxygen to tissue
physiological shunt (low VQ)
low ventilation, normal perfusion
decreased gas exchange
d/t obstruction like a mucus plug in the tube
physiological shunt (high VQ)
High VQ (good ventilation) but poor perfusion = alveolar dead space
I.e. PE, cardiogenic shock